Forming tool, in particular a kneading tool

ABSTRACT

The invention relates to a forming tool, in particular a kneading tool, which has a base body ( 12′ ), in which at least one forming element ( 21 ) is disposed, inclined at a first angle of inclination (α 1 ) to a central axis (M) of the deformation tool ( 12 ), which results in the determination of an inlet chamfer (S) of the forming element ( 12 ). According to the invention, it is provided that in the surface ( 21′ ) of the forming element ( 21 ) running in an inclined manner below the first angle of inclination (α 1 ) a recessed surface structure ( 22 ) is formed, which has at least one recess ( 23 ) with a trailing edge ( 23   a ), and that the trailing edge ( 23   a ) of said recess ( 23 ), related to the inlet chamfer (S) of the forming element ( 21 ) defined by the first angle of inclination (α 1 ), has a second angle of inclination (α 2 ), which is oriented towards the opposite direction with regard to the first angle of inclination (α 1 ), and the absolute value thereof is larger than or equal to the absolute value of the first angle of inclination (α 1 ).

The invention relates to a forming tool, in particular a swaging tool,which has a base body, in which at least one forming element isprovided, which is inclined at a first angle of inclination to a centralaxis of the forming tool, thereby determining an intake slope of theforming tool.

Such a forming tool is known from DE 103 28 052 B4 of the applicant andis used for the forming, in particular for the swaging, of work piecesin a swaging machine. During such a forming process performed by meansof the known forming tools substantial axial forces acting upon the workpiece are created, which is true for a feed swaging process as well asfor a recess swaging process. These forces can result in adisadvantageous manner in damage symptoms on the work piece, whichappear in form of bulgings or cripplings. The axial force created by theforming tools furthermore puts stress on the forming machine as well ason the feed system for the work piece and on the clamping device holdingthe workpiece, since the afore-mentioned units have got to compensatethe axial forces generated by the forming process. In order tocounteract these axial forces, DE 103 28 052 B4 discloses that on thesurface of the forming element of the forming tool an elevated,relief-like and wave-like surface structure is provided, which has got aplurality of elevations. Via these elevated surface structure on thesurface of the forming element a forming tool is created, which has gotthe advantage that the areas of the work pieces acted upon with thisforming tool have got a high surface quality. A further reduction of thestress created by the axial forces during the forming process is stilldesired.

It is the object of the present invention to further develop a formingtool of the afore-mentioned kind, so that by means of the inventiveforming tool a reduction of the axial forces is achieved.

This object is solved by the invention in that in the surface of theforming element being inclined with the first angle of inclination arecessed surface structure is formed, having at least one recess with adeclining face, and that the declining face of this recess has got, inrelation to the intake slope of the forming element, a second angle ofinclination, which is orientated in an opposite direction with regard tothe first angle of inclination and the absolute value thereof is largerthan or equal to the absolute value of the first angle of inclination.

By the inventive measures it is achieved in an advantageous way that inthe surface of the forming element at least one, preferably a pluralityof recesses are provided, the declining face of which is declined largerthan the one of the forming element and is oppositely orientated to itsdeclination. By this it is achieved that, when radial forming forces actupon the work piece, the declining faces of the recesses assimilate theaxial force component, so that the axial forces acting upon the formingmachine in the feeding direction and being generated by the workingprocess are reduced.

An advantageous further development of the invention provides that atleast one recess, preferably all recesses of the surface structure beingprovided in the surface of the forming element are arranged orthogonallyor essentially orthogonal to its longitudinal direction. These measuresgot the advantage that such an arrangement of the recesses of theinventive surface structure provides that only a very small torsion loadacts upon the work piece, which is created when the forming tool rotatesduring the forming process around the stationary work piece. The recessbeing arranged orthogonally to the longitudinal direction and hence inthe feed direction of the work piece therefore results in anadvantageous way not only in small axial forces, but yields that theforming tool only impacts no or only a small torsion force on the workpiece.

A further advantageous development of the invention provides that atleast two recesses of the surface structure of the forming element ofthe inventive forming tool run parallel or at least essentially parallelto each other. Such a measure has got advantages in relation to a smalltorsion load of the work piece acted upon by the inventive forming tool,and in particular, if, according to a further advantageous developmentof the invention, it is provided that at least two recesses of thesurface structure of at least one forming element run essentiallystraight.

A further advantageous development of the invention provides that atleast two recesses of the surface structure of the inventive formingtool are arranged inclinedly to the longitudinal direction of theforming element. Such a measure results in that higher torsion load actupon the work piece as it would be in the case of recesses beingarranged orthogonal to the longitudinal direction of the forming elementand hence to the feed direction of the work piece. But the angledarrangement of the recesses of the surface structure has got theadvantage that in the case of work pieces, for which a torsion load doesnot appear to be disturbing, a further reduction of the axial forcesacting upon the feeding device and hence opposite to the feedingdirection of the forming machine is achieved.

Further advantageous developments of the invention are the subjectmatter of the dependent claims.

Further details and advantages of the invention are given in theexemplary embodiment, which is described by means of the figures. Theyshow:

FIG. 1: a front view of the exemplary embodiment,

FIG. 2: a longitudinal section through the forming tool of FIG. 1 alongthe line II-II,

FIG. 3: a schematical representation of the surface structure, and

FIG. 4: a schematical representation of a tool head of a swaging machinewith a forming tool according to FIGS. 1 to 3.

Before in details the exemplary embodiment of a forming tool generallydesignated with 12 is described, for the sake of an easier understandingthe basic actions occurring in a forming process carried out by means ofsuch an forming tool are described: FIG. 4 shows a swaging headgenerally designated with 1 of a swaging machine, this means a tool headof a swaging machine, which has a swaging axle 2 and—in the casedescribed—four swaging modules being radially slightable. Each swagingmodule has got a swaging plunger 10, having at its radially outer end aroller path 4, which is acted upon periodically by pressure rollers 6being contained in a roller cage 5, in that the swaging axle 2 and/orthe roller cage 5 is driven by an outer ring 7. The pressure rollers 6hereby are supported by the outer ring 7. The swaging modules containbesides the swaging plunger 10 furthermore an adjustment plate 11 andthe forming tool 12. Such a swaging head 1 is generally known andtherefore it is not necessary to describe it further in details.

In order to produce from a tube- or rod-like initial work piece an endproduct, which has got in a first section still the non-reduced initialdiameter of the initial work piece, which has got in a second section adiameter being reduced due to the forming process, and which has atransition section between the first and second section, in which theouter diameter of the work piece increases continuously from the reduceddiameter to the initial diameter, so that in the final work piece theaxially inclining transition section is formed, it is provided that theforming tool 12 has got—as it can be seen from FIG. 2—a forming element21 being provided in a base body 12′ of the forming tool 12, which isarranged under a defined first angle of inclination α₁ to the centralaxis M of the forming tool 12 and hence to the feed direction of thework piece. Such a forming tool 12 is known and therefore there is noneed to describe it further. For the sake of an easier understandingonly it has got to be explained that the radial forming force, which isgenerated by the forming tool, creates, due to the angled arrangement ofthe forming elements 21, a force acting in the axial direction of thework piece, which stresses the work piece and must be compensated by afeeding device (not shown) of the forming machine, by means of which thework piece is fed during the forming process.

In order to better compensate these axial forces and to reduce the axialload of the work piece, which can lead to cripplings and bulgings, aswell as the one of the feeding device, the described forming tool 12 nowprovides that in a surface 21′ of the forming element 21 a—in relationto the surface 21—recessed surface structure 22 is provided, which hasgot (see FIG. 2) at least one recess 23 and usually a plurality ofrecesses 23. The detailed formation of the surface structure 22 is nowdescribed by means of FIG. 3, in which an exemplary embodiment thereofis shown. But it must be stressed that the angles, radii and furtherdimensions as well as the surface structure 22 shown there are only ofexemplary nature and not to affect the generality of the followingexplanations:

FIG. 3 shows a cross section through the surface structure 22 shown inFIG. 2. One can see the surface 21′ of the forming element 21 of theforming tool 12 and further, that the surface structure 22 is not—as itis the case of the forming tool explained at the beginning —provided onthe surface 21′, and is therefore not elevated. Contrary to that, it isprovided that the recesses 23 are arranged in the surface 21′ of theforming element 21. In the exemplary embodiment described, theinclination of intake slope S of the forming element 21, namely thefirst angle of inclination, is α₁ =10°, in relation to the central axisM of the tool. Each of the recesses 23 has got a declining face 23 a andan inclining face 23 b, wherein—as shown in FIG. 4—the declining face 23a of the recess 23 is provided under a second angle of inclination of(in this case:) α₂=29° in respect to the intake slope S. The inclinationof the faces 23 a therefore has got a value of α₂−α₁ in respect to thecentral axis M. The inclination of the declining faces 23 a of recesses23 is oppositely orientated to the first angle of inclination α₁defining the slope of the forming element 21 and the absolute value ofthe second angle of inclination α₂ is here larger than the one of thefirst angle of inclination α₁ of the forming tool 12. The oppositeorientation of the inclinations of the forming element 21 and thedeclining faces 23 a of the recesses 23 brings forth that the axialforces, which are generated by the swaging modules, are at leastpartially assimilated by the forming tool 12 and therefore do not actupon the work piece and/or the feeding device of the forming machine,since these axial forces are assimilated by the faces 23 a beingarranged oppositely to the inclination of the forming element 21. Thedeclining faces 23 a of the recesses 23 therefore form a kind of counterbearing for these axial forces and deviate them in the forming tool 12:The substance of the work piece of the areas being above the recesses 23recede in these recesses, so that the declining faces 23 a of therecesses 23 act upon the work piece in the feed direction.

It is evident for the person skilled in the art that the afore-mentionedexemplary values of the first angle of inclination of α₁=10° and of thesecond angle of inclination α₂=29° only have got an exemplary character.Important is only that the faces 23 a are inclined in relation to theintake face S, so that the absolute value of the second angle ofinclination α₂ is equal to the absolute value of the first angle ofinclination α₁.

It must be noted in this context that the wave-like shape of the surfacestructure 22 is not compulsory. It is possible too to form the recesses23 saw tooth-like, wherein the straightly declining face 23 a of such asaw tooth at least partially assimilates the axial forces.

As it can be seen from FIG. 4, the surface structure 22 has got at leastone, but in practice a plurality of recesses 23, which are preferablyarranged parallel or essentially parallel to each other and—once againpreferably—essentially orthogonal to the longitudinal direction of theforming tool 12 and in this way to the feeding direction V of the workpiece. But it is possible too that at least one of the recesses 23 isnot—as shown in the figures—provided orthogonal to the longitudinaldirection of the forming tool 12, but it is arranged in a defined anglethereto.

Concludingly, it must be stated that the described design of the formingtool 12 with a recessed surface structure 22 in combination with thedescribed formation of the recesses 23 and in particular with the one ofthe declined faces 23 a, a forming tool 12 is generated which excels inthat a substantial reduction of the axial forces acting upon the workpiece and/or the feed device of the forming machine is achievable.

1. Forming tool, in particular a swaging tool, having a base body (12′),in which at least one forming element (21) is provided, which isinclined at a first angle of inclination (α₁) to a central axis (M) ofthe forming tool (12), thereby determining an intake slope (S) of theforming element (21), characterized in that in the surface (21′) of theforming element (21) being inclined with the first angle of inclination(α₁) a recessed surface structure (22) is formed, having at least onerecess (23) with a declining slope (23 a), and that the declining face(23 a) of this recess (23) hast got, in relation to the intake slope (S)of the forming element (21) defined by the first angle of inclination(α₁), a second angle of inclination (α₂), which is orientated in theopposite direction with regard to the first angle of inclination (α₁)and the absolute value of which is larger than or equal to the absolutevalue of the first angle of inclination (α₁).
 2. Forming tool accordingto claim 1, characterized in that the surface structure (22) is formedwave-like.
 3. Forming tool according to claim 1, characterized in thatat least one recess (23) is formed saw tooth-like.
 4. Forming tool,according to claim 1, characterized in that at least two recesses (23)of the surface structure (22) of at least one forming element (21) ofthe forming tool (12) are arranged essentially parallel to each other.5. Forming tool, according to claim 1, characterized in that at leastone recess (23) of the surface structure (22) of at least one formingelement (21) of the forming tool (12) is provided essentially orthogonalto the longitudinal direction of the forming tool (12).
 6. Forming tool,according to claim 1, characterized in that at least one recess (23) ofthe surface structure (22) of at least one forming element (21) of theforming tool (12) runs essentially straight in a direction orthogonal tothe feed direction (V) of the work piece.
 7. Forming tool, according toclaim 1, characterized in that at least one recess (23) of the surfacestructure (22) of at least one forming element (21) of the forming tool(12) is formed curved or wave-like.
 8. Forming tool, according to claim1, characterized in that at least one recess (23) of the surfacestructure (22) of at least one forming element (21) of the forming tool(12) is arranged angled to the longitudinal direction of the formingtool (12).
 9. Forming machine, in particular a swaging machine, having aforming tool (12) for radially impacting a work piece, characterized bya forming tool (12), according to claim
 1. 10. Forming machine, inparticular a swaging machine, having a forming tool (12) for radiallyimpacting a work piece, characterized by a forming tool (12), accordingto claim
 2. 11. Forming machine, in particular a swaging machine, havinga forming tool (12) for radially impacting a work piece, characterizedby a forming tool (12), according to claim
 3. 12. Forming machine, inparticular a swaging machine, having a forming tool (12) for radiallyimpacting a work piece, characterized by a forming tool (12), accordingto claim
 4. 13. Forming machine, in particular a swaging machine, havinga forming tool (12) for radially impacting a work piece, characterizedby a forming tool (12), according to claim
 5. 14. Forming machine, inparticular a swaging machine, having a forming tool (12) for radiallyimpacting a work piece, characterized by a forming tool (12), accordingto claim
 6. 15. Forming machine, in particular a swaging machine, havinga forming tool (12) for radially impacting a work piece, characterizedby a forming tool (12), according to claim
 7. 16. Forming machine, inparticular a swaging machine, having a forming tool (12) for radiallyimpacting a work piece, characterized by a forming tool (12), accordingto claim 8.